Message-ID: <51877970.8010303@intel.com>
Date: Mon, 06 May 2013 17:35:44 +0800
From: Alex Shi <alex.shi@intel.com>
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To: Paul Turner <pjt@google.com>
CC: Michael Wang <wangyun@linux.vnet.ibm.com>, Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Borislav Petkov <bp@alien8.de>, Namhyung Kim <namhyung@kernel.org>,
        Mike Galbraith <efault@gmx.de>,
        Morten Rasmussen <morten.rasmussen@arm.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Preeti U Murthy <preeti@linux.vnet.ibm.com>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de>,
        Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH v5 7/7] sched: consider runnable load average in effective_load
References: <1367804711-30308-1-git-send-email-alex.shi@intel.com> <1367804711-30308-8-git-send-email-alex.shi@intel.com> <518724D1.9040006@linux.vnet.ibm.com> <51874229.8050202@intel.com> <5187609C.5050209@linux.vnet.ibm.com> <518763B0.30200@intel.com> <51876AFE.80906@linux.vnet.ibm.com> <CAPM31RK-N=Cnt3cBo1f6er6TewQJKY+fgdj9QHvKziHe+TxTxw@mail.gmail.com>
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On 05/06/2013 05:06 PM, Paul Turner wrote:
> I don't think this is a good idea:
> 
> The problem with not using the instantaneous weight here is that you
> potentially penalize the latency of interactive tasks (similarly,
> potentially important background threads -- e.g. garbage collection).
> 
> Counter-intuitively we actually want such tasks on the least loaded
> cpus to minimize their latency.  If the load they contribute ever
> becomes more substantial we trust that periodic balance will start
> taking notice of them.

Sounds reasonable. Many thanks for your input, Paul!

So, will use the seconds try. :)
> 
> [ This is similar to why we have to use the instantaneous weight in
> calc_cfs_shares. ]
> 


-- 
Thanks
    Alex
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